Time Phases of Acute Radiation Syndrome (ARS) - Dose Range 1-2 Gy

• 1 to 2
• 2 to 4
• 4 to 6
• 6 to 8
• Greater than 8
• Caveats and comments

Timeline: 1-2 Gy

ARS time phases and approximate whole body dose from exposure: 1-2 Gy

Predominant Manifest Illness Subsyndromes	Phases
	Prodromal	Latent	Manifest Illness (Critical Phase)	Recovery or Death
	Vomiting Onset: 2 hours after exposure or later Percent of victims who vomit at this dose: ~10-50% Diarrhea None Headache Slight Level of consciousness Unaffected Body temperature Normal Medical response Outpatient observation Hospitalization generally not necessary unless victim has underlying immunocompromise, trauma, chronic illness, etc., that predispose to a worse outcome.	Duration From end of prodrome through day 21-35 Epilation None Medical response Hospitalization generally not necessary. Post-event monitoring may be assisted by laboratory tests that estimate dose, e.g., sequential CBCs and dicentric chromosomes.	Onset > 30 days after prodrome Duration Depends on dose and underlying host factors Possible clinical effects Fatigue Weakness Lethality None likely from radiation alone Medical response As needed for signs/symptoms Counseling and long-term effects monitoring may be helpful	Recovery Expected unless complicated by trauma or chronic illness Counseling and long-term effects monitoring may be helpful and is critical for pregnant victims. Psychological support helpful